Detection of drug resistance genes of mycobacterium tuberculosis by rolling circle amplification technique with multicolor fluorescent probes / 中华预防医学杂志

The aim of this study was to construct a simple, rapid and ultra-sensitive optical biosensing technique based on rolling circle amplification (RCA), and to apply it to multiple detection of drug-resistant genes of mycobacterium tuberculosis. The common mutation sites of isoniazid, rifampicin and streptomycin resistance genes are katG315 (AGC➝ACC), rpoB531 (CAC➝TAC) and rpsL43 (AAG➝AGG). For these three gene sites, from February 2020 to May 2021, in the Department of Laboratory Medicine of the First Affiliated Hospital of Army Military Medical University, the padlock probe (PLP), primers and capture probes were designed. And a solid-phase RCA constant temperature amplification reaction system based on magnetic beads was constructed and the experimental parameters were optimized. The RCA products were accurately captured by the multicolor fluorescent probes (Cy3/Cy5/ROX), and the single-tube multiple detection of three mutation genes was realized. The sensitivity, specificity and linear range of this method were further verified. The results showed that the response range of katG315 in the same reaction system ranged from 1.0 pmol/L to 0.1 nmol/L. The response range of rpoB531 and rpsL43 ranged from 1.0 pmol/L to 50.0 pmol/L and 1.0 pmol/L to 20.0 pmol/L, and the method had good specificity and sensitivity, and could accurately identify single base mutations in mixed targets, with the minimum detection limit as low as 1.0 pmol/L. The recoveries of simulated serum samples were 95.0%-105.2%. In conclusion, the constant temperature amplification multiple detection method constructed in this study can quickly realize the single-tube multiple detection of three drug resistance mutation sites. This technology is low-cost, simple and rapid, and does not rely on large equipment, providing a new analysis method for pathogen drug resistance gene detection.

Effect of CDK1 Interferes with the Regulation of PLK1, Aurora B and TRF1 on the Proliferation of Leukemia Cells / 中国实验血液学杂志

OBJECTIVE@#To investigate the effect of CDK1 interference regulation of PLK1, Aurora B and TRF1 on the proliferation of leukemia cells.@*METHODS@#The human myelogenous leukemia cell line HL-60 was selected as the research object, and the effect of TRF1 expression and its changes on cell proliferation and cycle was investigated by regulating intracellular CDK1 expression. The objects were divided into 5 groups, including control group, shRNA-NC group, CDK1-shRNA group, pcDNA group and pcDNA-CDK1 group. RT-PCR was used to detect the CDK1 expression of cells in each group; colony formation was used to detect the proliferation of the cells. Western blot was used to detect the expression of CDK1, PLK1, Aurora B, TRF1, and cyclin p53, p27, cyclinA.@*RESULTS@#The phosphorylation level of PLK1, Aurora B and the expression of TRF1 in the CDK1-shRNA group were significantly down-regulated as compared with those in the control group (P<0.05). Compared with the control group, the cells in CDK1-shRNA group showed lower clone formation rate, the increasing of cycle-associated proteins p53 and p27 and the decreasing of cyclinA expression (P<0.05). It was shown that interfered CDK1 expression could inhibit the proliferation of HL-60 cells and prolong the time that they enter mitosis, thereby extending the cell cycle. Compared with the control group, the overexpressed CDK1 in the pcDNA-CDK1 group made the phosphorylation level of PLK1, Aurora B, and TRF1 expression increase significantly (P<0.05), also the colony formation rate (P<0.05). The cycle-related proteins p53 and p27 was down-regulated, while cyclinA expression was up-regulate significantly (P<0.05). The results indicted that overexpressed CDK1 could stimulate adverse reactions, thereby promoting the proliferation of HL-60 cells and shortening the cell cycle.@*CONCLUSION@#Knocking out CDK1 can inhibit the phosphorylation of PLK1 and Aurora B and negatively regulate TRF1, thereby inhibiting the proliferation of leukemia cells.

The efficacy and safety of ticagrelor versus clopidogrel in elderly patients with acute coronary syndrome undergoing percutaneous coronary intervention / 中华心血管病杂志

Objective: To compare the efficacy and safety of ticagrelor and clopidogrel in elderly Chinese patients with acute coronary syndrome (ACS) underwent percutaneous coronary intervention (PCI) in the real world. Methods: This study is a post-hoc analysis of a single center, retrospective cohort study. Between March 2016 and March 2018, elderly (age≥65) ACS patients who underwent PCI in the General Hospital of Northern Theater Command were included in the study. The patients were grouped according to P2Y12 receptor inhibitor. The primary endpoints of this study were ischemic events during the 2-year follow-up, which were defined as the composite of cardiac death, myocardial or stroke. The secondary efficiency endpoints included all-cause death and BARC 2, 3, 5 bleeding events. Results: A total of 4 022 elderly (mean age: (71.5±5.3) years) ACS patients were included in this study. Based on the choice of P2Y12 receptor inhibitor, patients were divided into clopidogrel (n=3 201) and ticagrelor (n=821) groups. Incidences of ischemic events (3.2% (26/821) vs. 5.6% (179/3 201), P=0.005) at 2 years were significantly lower in ticagrelor group compared to clopidogrel group. BARC 2, 3, 5 bleeding events (1.7% (14/821) vs. 1.6% (52/3 201), P=0.818) were comparable between the two groups. The incidence of all-cause death (1.5% (12/821) vs. 4.1% (132/3 201), P=0.005) were also lower in the ticagrelor group compared to the clopidogrel group. Clinical outcomes were consistent after adjusting for confounding factors, the incidence of ischemic events (HR= 0.637, 95%CI 0.409-0.991, P=0.046) and all-cause mortality (HR=0.402, 95%CI 0.213-0.758, P=0.005) was significantly lower in the ticagrelor group compared with the clopidogrel group. Risk of BARC 2, 3, 5 bleeding events were similar between the two groups (HR=0.957, 95%CI 0.496-1.848, P=0.897). Conclusion: In real-world clinical practice, for elderly patients with ACS undergoing PCI, ticagrelor use might reduce the incidence of long-term ischemic events and all-cause death without increasing the risk of bleeding.

Establishment of reference intervals and transfusion criterion for Sonoclot analysis / 华中科技大学学报（医学）（英德文版）

Sonoclot analyzer has been widely used in many countries. But the reference intervals provided by the manufacturer were derived from only 45 participants, and there was no cut-off value for transfusion for Sonoclot analysis. This study aimed to establish reference intervals and transfusion criterion for Sonoclot analysis. Volunteers were recruited from healthy Chinese adults and patients undergoing cardiac surgery. Blood samples were withdrawn from forearm vein and measured for activated clotting time (ACT), clot rate (CR), platelet function (PF), activated partial thromboplastin time (APTT), fibrinogen concentration (FIB), and platelet count (PLT). The reference intervals were determined by the nonparametric method. Cut-off values were determined by the receiver operating characteristics curve. A total of 135 healthy volunteers and 281 patients were enrolled. The 95% reference intervals were 96-195 s, 22-51 signal U/min, >1.6 for ACT, CR, PF respectively. In the 281 patients, the results of APTT, FIB, PLT, ACT, CR, and PF ranged from 20.5-300.0 s, 0.28-4.11 g/L, (19.0-387.3)×109/L, 80-514 s, 2.9-74 signal U/min, and 0.1-5.1 respectively. The cut-off values for transfusion were >208, ≤14, and ≤1.3 for ACT, CR, PF respectively. The cut-off values of Sonoclot analysis were within the manufacturer's reference intervals, while they were outside the reference intervals established in this study. The results suggested that the manufacturer's reference intervals were not suitable for Chinese. The reference intervals and cut-off values established in this study will be helpful to Chinese patients.

Anti-tumor activity of components isolated from purple sweet potato polysaccharides / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To isolate and purify components from polysaccharides of purple sweet potato (PPSP) and to test their anti-tumor activity.</p><p><b>METHODS</b>DEAE-Cellulose and CM-Cellulose exchange chromatography were applied to separate components of PPSP. The anti-tumor activities of each component were measured by MTT assay on Hela and HepG(2) cells and their monosaccharide composition were analyzed by TLC chromatography, followed by infrared spectroscopy studies.</p><p><b>RESULTS</b>Through weak anion exchange chromatography and gradient elution by sodium chloride solution, four components were separated and named as PPSP, PPSPII, PPSPIII and PPSPIV, respectively. MTT tests showed that PPSP II and PPSPIII inhibited Hela and HepG2 tumor cells in a certain extent. The structural analysis revealed that PPSPI was mainly composed of glucose and galactose, PPSP II was composed of glucose and had a typical absorption peak of β-D-glucose chitosan pyranose, PPSP III was a glycoprotein showing a protein absorption peak.</p><p><b>CONCLUSION</b>Four components were separated from PPSP successfully, among which PPSP II and PPSP III shows anti-tumor activities on Hela and HepG(2) cells in vitro.</p>